A human choline acetyltransferase gene has been isolated from the human brain (McGeer P. L. et al., Life Sci., 34:2319–2338 (1984)). Choline acetyltransferase is specifically expressed in cholinergic neurons. Choline acetyltransferase is an enzyme which catalyzes a reaction which yields the neurotransmitter acetylcholine. Although choline acetyltransferase expression has been found in both neurons and certain non-neuronal tissues, such as placenta (Schuberth, J., Biochim. Biophys. Acta, 122:470–481 (1966)) and spermatozoa (Ibanez, C. F. and Persson, H., Eur. J. Neurosci., 3:1309–1315 (1991)), the expression of this enzyme is largely limited to certain neurons.
The 5′ flanking region of the human choline acetyltransferase gene differs from the rodent gene in that the rodent gene has a “TATAA” box consensus sequence upstream of the transcription start site, but no such element is found in the human gene. The rodent gene also differs in that it contains at least three promoters and the sequence corresponding to only one of the promoters, the M type, is found in the human gene (Hersh, L. B., et al., J. Neurochem., 61:306–314 (1993)).
The control of motor behavior constitutes one of the most important functions of the central nervous system. Numerous regions of the brain are involved in this process that is integrated ultimately in the motor neurons of the spinal cord, the “final common path” in the control of movement. These neurons, which lie in the ventral horn, exhibit a cholinergic phenotype and, therefore, express choline acetyltransferase. Choline acetyltransferase is a specific marker of the cholinergic system.